Electric oven



F. W. MOFFAT. ELECTRIC OVEN. APPLICATION FILED JUNEH. I920.

Patented Dec.12,1922.

ZNVE'NTUH.

Patented Dec. 12, 1922.

UNITED STATES FREDERICK W. MOFFAT, OF WESTON, ONTARIO, CANADA.

ELECTRIC OVEN.

Application filed June 14,

To all whom it may concern:

Be it known that I, FREDERICK W. Mor- FAT, of the city of Weston, in the county of York, Province of Ontario, Canada, have invented certain new and useful Improvements in Electric Ovens, of which the following is a specification.

This invention relates particularly to the connections between the electric heating element of the oven and the wires conveying current thereto. The general practice at the present time is to make the connections inside the oven structure, an arrangement which possesses many disadvantages, and my object is to devise a construction in which the connections are all made outside the oven structure.

I attain my object by means of the constructions hereinafter described and illustrated in the accompanying drawings in which Fig. 1 is a vertical section through part of an oven provided with my improved connections;

Fig. 2 a plan view of the same, partly broken away and partly in section;- and Fig. 3 an end view of the insulating block.

In the drawings like numerals of reference indicate corresponding parts in the different figures.

As is common, the oven is provided with hollow metal double walls, the outer metal wall 1 being spaced from the inner metal wall 2, the space being filled in with mineral wool or other heat insulating material. \Vithin the-oven an electric heating element is suitably supported. In an oven such as shown, this heating element is located in a well 3 formed in the bottom of the oven. WVhile any form of heating element may be employed, I show a plurality of supporting bars a of insulating material supported on a suitable base, the resistance wiring being strung on or through these bars as shown. The heating element, as shown, is wired to give three heats, which necessitates the use of two separate resistances having four free ends 6. These ends are integral with the resistance wiring and are led through the wall of the oven to the outside thereof for connection with the circuit or circuits through which electric energy is supplied.

To insulate the ends 6 of the resistance wiring from the metal walls of the oven and to support the outside terminals to which the ends are connected, I provide 1920. Serial No. 389,045.

a block 7 of suitable insulating material. This block will usually be formed of some form of earthenware or porcelain. Through this block are formed holes 8 through which the ends 6 of the resistance wiring pass. At the outer end of the block are secured the terminals 9.

In the preferred form the block is L-shaped, its lower leg through which are formed the holes 8 abutting at its inner end the inner wall 2 of the oven. Extensions 10 are formed at the inner end of the block, preferably cylindrical in form, extending through suitable holes formed in the wall 2. The inner ends of the holes 8 are at the inner ends of these extensions and from them the ends 6 of the resistance wiring will pass directly to the supporting bars at. The outer end ofthe L-shaped block is exposed through an opening in the outer wall 1. About this opening is secured a metal frame 11 which engages the block and thus holds it in position against the inner wall 2.

The terminals 9 are formed as bolts secured in holes formed in the outer leg of the block 7, the holes being counter-bored to provide recesses 12 in which the bolt heads are received, being thus absolutely protected from any possbility of contact with any of the metal parts of the oven well.

To the outer end of the block 7 is applied the cover 13. When the latter is in place, its edges are partly overlapped by the frame 11 so that it is accurately positioned with regard to the block.

Between the end of the block cover is formed a recess 1-1- provid' 1g room for the outer ends of the terminals 9. Through the sides of this recess are formed the openings 15 for the passage of wires 16, which in practice lead to theswitch controlling the supply of electric energy. The

an d the cap is held in place by the pivoted spring tongue 17 secured to the metal frame 11.

Vhile it is preferable to make the block 7 in one piece it might be made in sections without departing from the spirit of my invention.

From the construction described it will be seen that the terminals are brought right me do paired. Perfect insulation is also provided for all parts carrying current.

l Vhat l claim as my invention is:

1. In an electric oven provided with a hollow metal double wall, the combination of resistance wiring suitably supported within the oven; at block of insulating material extending through the oven wall from the outside to the inside and provided with a plurality of holes through each of which the end 01" a resistance wire extends; and terminals carried by said block at its outer end to which said resistance wiring is connected outside the end of the block, the outer ends of said terminals being adapted for connection to an external circuit.

2. Apparatus constructed as set forth in claim 1 provided with a cap fittingthe outer endiof the insulating block and torn1- ing with the end of the block a cavity enclosing the terminals.

3. Apparatus constructed as set forth in claim 1 in which the insulating block is l..- shaped, the holes for the passage of the resistance wires extending lengthwise through one leg of the block, the terminals being secured through the other leg of the block.

4-. In an electric oven provided with a hollow metal double wall, the combination of resistance wiring suitably supported within the oven; a block of insulatinp; material extending through the outer wall and abutting the inner wall; a plurality of extensions on said block extending through openings in the inner wall, holes extending eas es through the block and said extensions through which the resistance wiring errtends; and terminals carried by said block at its outer end to which said resistance Wiring is connected.

5. In an electric oven provided with a hollow metal double wall, the combination of resistance wiring suitably supported within the oven; an L-shaped block of insulating material having one leg fitting an opening in the outer wall and the other leg extending through the space between the walls and abutting against the inner wall, the latter leg being provided with a plurality of holes for the passage of the resistance wiring; terminals carried by the first men tioned legat its outer side to-which the resistance wiring is connected; and a metal frame secured outside the outer wall of the casing and engaging the block to retain it in position.

6.' Apparatus constructed as set forth in claim 5 provided with a plurality of extensions extending through the inner wall of the oven, the holes for the passage of the resistance wiring extending through said extensions.

7. Apparatus constructed as set forth in claim 5 provided with a cap fitting the outer end of the insulating; block and forming with the end of the block a cavity enclosing the terminals.

Signed at Toronto this 8th day of June FREDERICK W. MUFFAT. 

